Patent Document 1 discloses, for example, a contactless system that supplies power from a power supplying device to a power receiving device in a contactless manner. The contactless power supplying system delivers high-frequency current to a primary coil and supplies power to an electronic device through a secondary coil using electromagnetic induction. This system does not require a conventional electric cord that connects a power supply and an electronic device. Patent Document 2 discloses an example of a technique for applying a contactless power supplying system to a household.